1. Field of the Invention:
The present invention relates to a positioning system for positioning a movable element in any of a plurality of positions along a linear, circular, or otherwise shaped path.
2. Description of the Prior Art:
Some conventional positioning systems for moving and positioning a movable element in a desired position along a linear, circular, or otherwise shaped path employ a recently developed intelligent flexible positioning actuator which can stop the movable element in any position along the path, which position can freely be selected by a software program. According to one such positioning actuator, the position of a movable element is detected by an encoder, output pulses from the encoder are counted, and the movable element is moved by an air cylinder or the like and stopped in any desired position along the path while referring to the count.
The programmable positioning actuator, which can position the movable element in any position along the path while counting output pulses from the encoder, has too many functions, is too complex in operation and arrangement, and too expensive for such an application in which the movable element is simply required to be positioned in any one of a plurality of predetermined positions along the path. Furthermore, when the movable element is moved and stopped by an air cylinder or the like, the movable element may overrun the position where it is to be stopped. If an air cylinder is employed, the movable element is positioned thereby at a positioning error of about 1 mm, and hence the positioning accuracy is poor.